[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 311805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED AUG 31 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING
INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER
OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 1715 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION THIRTEEN DEVELOPED AT 31/1500 UTC AND ITS
CENTER WAS NEAR 28.8N 50.4W...MOVING NORTHEAST 11 KT. THE
ESTIMATED MINIMUM CENTRAL PRESSURE WAS 1009 MB. THE MAXIMUM
SUSTAINED WIND SPEEDS WERE NEAR 30 KT WITH GUSTS TO 40 KT.
PLEASE REFER TO THE LATEST NHC FORECAST ADVISORY UNDER AWIPS/
WMO HEADERS MIATCMAT3/WTNT23 KNHC AND THE PUBLIC ADVISORY
UNDER AWIPS/WMO HEADERS MIATCPAT3/WTNT33 KNHC. TROPICAL
DEPRESSION ACTUALLY DEVELOPED ON MONDAY OF THIS WEEK BUT THEN
IT WEAKENED AFTER ABOUT 24 HOURS. IT HAS REGENERATED THIS
MORNING BETWEEN BERMUDA AND THE AZORES. IT IS POSSIBLE THAT
THIS DEPRESSION MAY BECOME A TROPICAL STORM LATER TODAY.
THE BAND OF SHOWERS AND THUNDERSTORMS IS EAST OF THE SURFACE
CIRCULATION CENTER. SCATTERED TO NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS ARE FOUND FROM 27N TO 30N BETWEEN 47W AND 50W.
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS
ARE FOUND FROM 30N TO 34N BETWEEN 48W AND 52W. ISOLATED
MODERATE SHOWERS ALSO ARE SEEN FROM 26N TO 29N BETWEEN 50W
AND 60W. THE LONG-RANGE FORECAST FOR THIS DEPRESSION IS THAT
IT WILL MOVE NORTHEAST AND POSSIBLY BECOME EXTRATROPICAL BY
FIVE DAYS.

AN ATLANTIC OCEAN 1010 MB SURFACE LOW PRESSURE CENTER WAS NEAR
16N40W...MOVING WEST-NORTHWEST 10 KT. A BAND OF SHOWERS AND
THUNDERSTORMS CURVES FROM AN AREA TO THE NORTH OF THIS LOW
CENTER...TO ITS EAST...AND THEN TO THE SOUTH AND SOUTHWEST...
EVENTUALLY NEAR 14N40W 10N47W...AND FROM 14N TO 20N BETWEEN
35W AND 40W...AND EVEN STARTING TO CURL AROUND FROM THE NORTH
AND NORTHWEST A BIT FROM 18N TO 19N BETWEEN 40W AND 42W.
A MIDDLE TO UPPER LEVEL CYCLONIC CENTER IS NEAR 18N45W.
MIDDLE TO UPPER LEVEL DRY AIR IS CURLING AROUND THIS FROM THE
NORTHEAST NEAR 25N43W TOWARD THIS CENTER TO 14N48W. UPPER LEVEL
ANTICYCLONIC FLOW EXTENDS FROM NORTH OF THIS CENTER NEAR 23N38W
EASTWARD TO AT LEAST 23N24W.

...TROPICAL WAVES...

CARIBBEAN SEA TROPICAL WAVE MOVING ACROSS JAMAICA...ALONG
77W/78W SOUTH OF 19N MOVING WEST 10 TO 15 KT. UPPER LEVEL
ANTICYCLONIC WIND FLOW...ORIGINATING IN THE SOUTHWESTERN
CARIBBEAN SEA/COLOMBIA/PANAMA...IS ON TOP OF THIS WAVE.
SHOWERS AND THUNDERSTORMS WHICH WERE IN THE SOUTHWESTERN
CORNER OF THE CARIBBEAN SEA A FEW HOURS AGO HAVE BEEN
DISSIPATING WITH TIME. MIDDLE TO UPPER LEVEL DRY AIR IS
IN THE REGION FROM 13N TO 17N BETWEEN 74W AND 89W. ISOLATED
MODERATE SHOWERS AND THUNDERSTORMS FROM 18N TO 21N BETWEEN
80W AND 85W ARE IN AN AREA OF SOME UPPER LEVEL DIFFLUENT FLOW.

...THE ITCZ...

ITCZ 10N15W 9N24W 13N37W...13N42W 10N50W 10N60W. WIDELY
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS
STRETCH FROM SURINAME NEAR 5N TO 11N BETWEEN 50W AND 60W.
STRONG SHOWERS AND THUNDERSTORMS FROM 9N TO 11N BETWEEN 23W
AND 26W. WIDELY SCATTERED MODERATE SHOWERS ELSEWHERE FROM
FROM 5N TO 8N BETWEEN 13W AND 20W...AND FROM 6N TO 9N BETWEEN
23W AND 30W.

...DISCUSSION...

THE GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTER IS ALONG THE
NORTHERN PART OF THE SOUTH CAROLINA COAST. A RIDGE EXTENDS
SOUTHWESTWARD TO THE EASTERN GULF OF MEXICO. A STRONG AMOUNT
OF DRY AIR IN THE MIDDLE AND UPPER LEVELS OF THE ATMOSPHERE
IS ON THE EAST SIDE OF WHAT APPEARS TO BE A DEVELOPING TROUGH
IN SOUTH CENTRAL/SOUTHWEST TEXAS. THIS DRY AIR COVERS MOST OF
TEXAS...AND LOUISIANA WEST OF 91W. UPPER LEVEL EASTERLY WIND
FLOW IS MOVING ACROSS SOUTHERN MEXICO...BELIZE...AND GUATEMALA.
SHOWERS AND THUNDERSTORMS WERE IN THE SOUTHWESTERN GULF FIVE
HOURS AGO...BUT THOSE HAVE BEEN WEAKENING DURING THE LAST FEW
HOURS.

THE CARIBBEAN SEA...
ONE MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS IN
WESTERN HONDURAS...AND ANOTHER SUCH CYCLONIC CENTER IS JUST OFF
THE NORTH CENTRAL COAST OF JAMAICA. THESE TWO CENTERS MAY BE
CONNECTED BY A TROUGH...OR EVEN BY A SHEAR AXIS. SHOWERS WHICH
HAVE BEEN WEAKENING DURING THE LAST FEW HOURS ARE FOUND IN HAITI
EAST OF THE JAMAICA CENTER. A CARIBBEAN SEA TROPICAL WAVE WAS
MOVING ACROSS JAMAICA...ALONG 77W/78W SOUTH OF 19N MOVING WEST
10 TO 15 KT. UPPER LEVEL ANTICYCLONIC WIND FLOW...ORIGINATING IN
THE SOUTHWESTERN CARIBBEAN SEA...COLOMBIA...AND PANAMA...IS ON
TOP OF THIS WAVE. SHOWERS AND THUNDERSTORMS WHICH WERE IN THE
SOUTHWESTERN CORNER OF THE CARIBBEAN SEA A FEW HOURS AGO HAVE
BEEN DISSIPATING WITH TIME. MIDDLE TO UPPER LEVEL DRY AIR IS IN
THE REGION FROM 13N TO 17N BETWEEN 74W AND 89W. ISOLATED
MODERATE SHOWERS AND THUNDERSTORMS FROM 18N TO 21N BETWEEN 80W
AND 85W ARE IN AN AREA OF SOME UPPER LEVEL DIFFLUENT FLOW. THE
UPPER LEVEL ANTICYCLONIC WIND FLOW IN THE SOUTHWESTERN CORNER OF
THE AREA IS ASSOCIATED WITH A RIDGE FROM THE EASTERN CARIBBEAN
SEA WESTWARD.

THE ATLANTIC OCEAN...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTER IS ALONG THE
NORTHERN PART OF THE SOUTH CAROLINA COAST. A RIDGE EXTENDS
SOUTHWESTWARD TO THE EASTERN GULF OF MEXICO. A MIDDLE TO UPPER
LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 26N66W. A TROUGH IS
ALONG 30N58W 26N66W 22N76W IN BETWEEN THE BAHAMAS AND CUBA.
ISOLATED MODERATE SHOWERS ARE WITHIN 60 NM ON EITHER SIDE OF
LINE FROM THE ATLANTIC SIDE OF CENTRAL CUBA TO SOUTH FLORIDA
TO NORTH FLORIDA. AN UPPER LEVEL RIDGE RUNS FROM SOUTHERN PUERTO
RICO TO 22N60W TO 27N55W.

$$
MT

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